The present invention relates to an improved adjustable armrest for use on a chair and more particularly to an adjustable armrest engaged with a pneumatically operated cylinder so as to permit the armrest body to be vertically lifted up by actuation of a control stick or lowered down by a manual force exerted against the armrest body. An armrest mount having tracks defined thereon for mounting of the armrest body permits the armrest body to be slidably adjusted back and forth thereon. The armrest mount with the armrest body is mounted to a housing having a vertical hole for receiving the cylinder engaged with the underside of the armrest mount at the top end thereof and received in a tubular sleeve at the bottom. The tubular sleeve having a protrusion block and a retaining means for housing the cylinder is rotatably housed in the vertical hole with the protrusion block located in a wavy recess having a plurality of retaining cavities of the vertical hole so as to permit the housing along with the armrest body to be adjustably pivoted within a certain angular range with respect to the tubular sleeve.
Chairs have been designed and produced in many types to meet various needs of people and suit for occasions and places of different kinds. It is a primary concern in producing a chair to make a person feel comfortable and relaxed when sitting on a chair. There are many kinds of chairs available on the markets, such as swivel chairs, rocking chairs, office chairs, folding chairs and etc. The armrests designed for a chair are a critical portion in designing and producing a comfortable chair in addition to the backrest and seating portion of a chair. Armrests are very important because people feel comfortable and relaxed when sitting on a chair for a long time with their arms fitly resting on the armrests. In general, the armrests of a chair are fixed to the chair without adjustability, making people of different physical sizes uncomfortable in case their arms do not relaxedly rest on the armrests.
However, a prior art adjustable armrest using a locking pin to fit in differently positioned retaining holes so as to permit the armrests of a chair to be adjustable still has the following disadvantages:
1. the adjustment must be made in stagewise manner and can not be performed in a stageless way and the locking pin must be removed and engaged with the retaining holes in every adjustment.
2. the assembly of the prior art adjustable armrests is relatively complex and time consuming, resulting in the cost of production too high to compete on markets.